638195505 has 8 divisors (see below), whose sum is σ = 1021112832. Its totient is φ = 340370928.

The previous prime is 638195497. The next prime is 638195533. The reversal of 638195505 is 505591836.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 638195505 - 2³ = 638195497 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21273169 + ... + 21273198.

It is an arithmetic number, because the mean of its divisors is an integer number (127639104).

Almost surely, 2^638195505 is an apocalyptic number.

It is an amenable number.

638195505 is a deficient number, since it is larger than the sum of its proper divisors (382917327).

638195505 is a wasteful number, since it uses less digits than its factorization.

638195505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42546375.

The product of its (nonzero) digits is 162000, while the sum is 42.

The square root of 638195505 is about 25262.5316427313. The cubic root of 638195505 is about 860.9631830650.

The spelling of 638195505 in words is "six hundred thirty-eight million, one hundred ninety-five thousand, five hundred five".